It is commonly known in the art that surfaces are available that may be marked on with dry wipe markers, also known as dry erase markers or dry erasable markers. These markers use solvent based ink which dries to a powder after it has been applied to a surface, commonly a smooth, glossy, plastic surface. These markers commonly come in different colors.
When a user writes on a dry erasable writing surface using conventional dry erasable markers, the ink readily adheres to the surface and may be applied in thick or thin strokes. The ink, after it dries, will adhere to the dry erasable writing surface for a long period of time, e.g., at least several months, without significantly flaking or otherwise peeling away from the dry erasable writing surface.
The dry erasable marker ink, when applied, dries to a powder and may be readily wiped off from the dry erasable writing surface with a dry cloth or dry eraser. No solvent of any kind is needed in the erasing, hence these markers are known as "dry wipe," "dry erase," or "dry erasable." These terms are used interchangeably in the specification and claims.
One common dry erase marker is sold by the Sanford Corp., Bellwood, Ill. under the registered trademark, EXPO. The writing surfaces, commonly white in appearance, adapted for use with such markers are commonly known as dry erase boards, dry erasable boards, write boards or white boards. These terms also are used interchangeably in the specification and claims.
This method of erasable writing is to be contrasted with the earlier-known use of chalk on slate or other surfaces which were used as chalkboards. This is also to be contrasted with those surfaces where markers were used and the markings could only be removed by application of solvents such as water, or an organic solvent such as mineral spirits.
It also is commonly known to use various materials as projection screens for reflecting the projected light of movies, slides, or overhead projections so that the associated audience is able to perceive the projected light. Such materials are normally white, off-white or a light-color so as to best allow perception of the projected light and to allow such light to be perceived in the color range intended.
Prior to the present invention, dry erasable markerboards, while generally being white, have not served adequately as projection surfaces. This failure on the part of the prior art is due primarily to the high gloss surface of the dry erasable markerboards. Further, prior high quality projection surfaces were known, but, these projection surfaces were not able to be marked upon with dry erase markers and the markings then dry erased.